Diagnostic Value of 68Ga PSMA-11 PET/CT Imaging of Brain Tumors—Preliminary Analysis

Objective To evaluate the feasibility of using 68Ga PSMA-11 PET/CT for imaging brain lesions and its comparison with 18F-FDG. Methods Ten patients with brain lesions were included in the study. Five patients were treated cases of glioblastoma with suspected recurrence. 18F-FDG and 68Ga PSMA-11 brain scans were done for these patients. Five patients were sent for assessing the nature (primary lesion/metastasis) of space occupying lesion in brain. They underwent whole body 18F-FDG PET/CT scan and a primary site elsewhere in the body was ruled out. Subsequently they underwent 68Ga PSMA-11 brain PET/CT imaging. Target to background ratios (TBR) for the brain lesions were calculated using contralateral cerebellar uptake as background. Results In five treated cases of glioblastoma with suspected recurrence the findings of 68Ga PSMA-11 PET/CT showed good correlation with that of 18F-FDG PET/CT scan. Compared to the 18F-FDG, 68Ga PSMA-11 PET/CT showed better visualization of the recurrent lesion (presence/absence) owing to its significantly high TBR. Among the five cases evaluated for lesion characterization glioma and atypical meningioma patients showed higher SUVmax in the lesion with 68Ga PSMA-11 than with 18F-FDG and converse in cases of lymphoma. TBR was better with 68Ga PSMA PET/CT in all cases. Conclusion 68Ga PSMA-11 PET/CT brain imaging is a potentially useful imaging tool in the evaluation of brain lesions. Absence of physiological uptake of 68Ga PSMA-11 in the normal brain parenchyma results in high TBR values and consequently better visualization of metabolically active disease in brain.